JPS597702A - Turbine wheel and its manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a turbine wheel and a method for manufacturing the same.

Turbine packets and blades are subject to wear or erosion due to a number of factors. For example, in a steam turbine, the mechanical energy absorbed by the steam in the moving blades or packets and imparted to the driven equipment as the rotational movement of the shaft causes the steam to expand into the region of heat of evaporation. This is due to the dryness of the water vapor, which reduces the quality (dryness) of the water vapor. As the moisture content increases and the water vapor A lidi decreases, the buff [
-iゝ) The blade is more easily eroded. Moist steam is generally associated with the final stage of a condensing steam turbine, but with the 9fr. For power generation, steam with an A property of 20 to 30% is supplied, and for oil steam injection, steam with an A property of 80% is supplied. ,
In addition to the presence of water droplets, blade erosion is also a function of the droplet's velocity and its angle of impact. The presence of particles in the gas has a similar effect to the presence of water droplets. One solution to blade erosion is to use replaceable blades. Further, depending on the steam inlet and outlet conditions, conventional axial turbines are inadequate for low horsepower applications because of their partial steam introduction operation.

The present invention relates to solid wheels for turbines which, depending on the type and the materials used, are capable of very high tip speeds. The turbine associated with the present invention is a conventional A:V turbine.
Si1? It is more efficient than a radial flow turbine, and at least as efficient as a radial synflow turbine overall. This is because its rotational speed is much lower and therefore the mechanical losses are lower. Buffs 1 are machined on the outer diameter of the wheel. The nozzle ring construction is of the radial inflow type with a tapered or diverging nozzle and a small angle of incidence to maximize performance. Due to the geometry of the packet and the tangential inflow of water vapor from the nozzle, water droplets or solid particles moving at a lower velocity than the gas flow will impinge on the packet at a small angle, and the relative velocity between them will increase. The small J: resistance erosion is reduced and braking loss is minimized. The inlet casing and the exhaust casing are of medium slender construction to partially or fully introduce 41 the fluid moving at very high pressure. Since each turbine wheel has a directly machined packet, packet damage is less likely to occur. Furthermore, since the packets are constructed with a unique angle to the disc of the wheel, vibrations induced by the disc portion and the disc node are substantially eliminated. Either a one-piece structure or a through-bolt structure may be adopted for the wheel. Since the wheel is thus of rigid construction, the present invention is suitable for a wide range of gases such as superheated steam and saturated steam. By using gearing, any output shaft speed can be achieved with optimum turbine efficiency.

One object of the present invention is to provide a solid turbine wheel and a method of manufacturing the same.

Another object of the present invention is to provide a two-stage turbine solid wheel and a method for manufacturing the same.

Yet another object of the present invention is to provide a wheel that is highly resistant to moisture and particle attack, has low windage losses, and has low thrust capacity.

Furthermore, one purpose of this light (l!l) is to
・More efficient than the Leflow turbine, with 1 lower 711 power 1
1. To provide a radial introduction turbine that is overall at least as efficient as a radial inflow turbine.

Yet another object of the present invention is to provide an IC turbine suitable for use in connection with wet, steam, and dirty gases.

Basically, a plurality of packets are formed on the rim of a solid wheel, uniformly spaced from each other.

Each packet has a substantially semi-circular curved groove in which the wall of each packet is part of the cylindrical side and has straight extensions or legs on each side and an island in the center of the cylinder. It is formed by machining so as to be A-variable to adjacent buffs 1 so as to define the shape. The fluid overlying the motion flows between one side of the wall defining the curved groove and the island, and the flow is about 1
It transmits J-dimensional energy (to the wheel after being turned by 80 degrees) and is also applicable to curved and grooved shafts. Furthermore, the constituent materials 1'il of the parts are set at a design pressure, a set temperature of 61,
and may be appropriately selected depending on other points of the operating system F1.

In FIGS. 1 and 2, sign 10 generally indicates a two-stage solid wheel turbine. The turbine 10 includes an axial inlet 1-cushing 12, an exhaust volute casing 16, a volute cover 18, and a first stage nozzle ring 2.
0, the second stage nozzle assembly 22, the two-stage solid turpin wheel 20, the shirt 1-28, the balance screw, the ton seal ring 32, and the shaft seal ring 3. /l, bearing housing 36, bearings 38 and 3
It is /υ including 9. Wheel 26 and nozzle ring 20
A labyrinth seal 41 is used to seal the space between the two.

Further, the space between the wheel 26 and the nozzle assembly 22 is sealed by a labyrinth seal '12.43.4/I. Further, the space between the wheel 26 and the balance screw seal ring 32 is sealed by a labyrinth seal 45.

The inlet 1-casing 12 is preferably a one-piece molded piece of aluminum, such as aluminum-based stainless steel, and includes a short axial inlet pipe with a flange configured to be connected to a steam source and a nose. It consists of an inlet cone including a cone 13 and an inlet guide vane 14. Inlet [-Casing 1
2 serves as a means for connecting the steam source to the turbine 10 and also supports a nozzle ring 20 and a nozzle assembly 22, which are supported by the exhaust volute casing 16 via a volute cover 18. The volute cover 18 is formed as a one-piece shell with seven flanges to prevent fluid from leaking into and out of the exhaust volute casing 16, and also to protect the inlet casing 12, nozzle ring 20, and nozzle assembly. 22.

The exhaust volute casing 16 is a scroll-type or reaching-type volute that discharges fluid tangentially and is suitably formed as a one-piece carbon steel molding. ] The nozzle ring 20 and the nozzle assembly 22 are made of stainless steel.The nozzle ring 20 is a one-piece construction. It is a real ring type structure, and the nozzle assembly 20 has a three-piece structure consisting of members 22a and 221).The nozzle blades 21 and 23 are connected to the nozzle ring 20 and the part +4, respectively.
It is integrally formed in the thin wall portion of 22a. The angle and size of these nozzle blades 21 and 23 depends on the design load. Nozzle ring 20 and nozzle assembly 22
labyrinth seal carried by 41.42.43.
44 is also preferably made of stainless steel. More particularly, the first stage nozzle ring 20 is of the type that discharges fluid substantially tangentially to the first stage 26a of the turbine wheel 26. A nozzle blade 2 formed in a thin wall portion of a ring-shaped steel plate, that is, a nozzle ring 20.
1 Ct profile type root. The labyrinth seal 41 is located at the inner rim of the nozzle ring 20 and separates the inlet of the packet from the outlet 11i111. ing.

10- The nozzle ring 20 is inlet [casing 1
2). In a two-stage turbine as shown, the first stage nozzle ring 20 is attached to the second stage nozzle assembly 22, but in a single stage turbine the nozzle ring is directly connected to the exhaust volute casing 16. Installation: The second stage nozzle assembly tr integral 22 consists of two members: a nozzle ring member 2 similar to the nozzle ring 20;
2a, and a diaphragm-shaped disk member 22 having a labyrinth seal 42 on the inner rim portion and a labyrinth seal 43 on the side facing the second stage 261) of the wheel 26.
1). An axial guide vane 24 is provided at the outer edge of the disk member 221). The guide vanes 2/I may be machined directly on the disc member 221), and may also be machined directly on the disc member 221).
It may be a standard plate material welded to the disk member 221), or may be formed integrally with the disk member 221) if the disk member 22b is a cast product. Axial guide vanes 24 accomplish two purposes. The first purpose (
The second purpose is to provide tangential motion to the flow of water vapor, and the second purpose is to mechanically position and support the disk member 22h in the radial direction. The axial guide vanes 24 may be replaced by radially reversing vanes or blades (not shown) provided on the radially outer portion of the thin-walled portion opposite the nozzle ring 20. The nozzle ring member 22a and the disk member 22:) are assembled together to form an integral second stage nozzle assembly 22. In this case, each blade 23 of the nozzle ring member 22a is fastened using a penetrating stud (not shown) at the position where its thickness is greatest, and then the blades 23 are fastened to each other in order to improve the strength of the entire assembly. This may be done by welding. The first stage nozzle ring 20 and the second stage nozzle phase body 22 are supported inside the exhaust volute casing 16 in the illustrated embodiment.

The balance screw 1 hencheal ring 32 is a tubular ring member with a diametrical split and is used only in double stamp turbines. Labyrinth seal 45 is provided on the inner surface of seal ring 32. Seal ring 32
is fastened to the bearing housing 36 by a hole 1- passing through the bearing housing 36 in its thickness direction. The shaft seal ring 34, in the illustrated embodiment, includes two intermediate pressure relief boats 70 and 71 that reduce the steam pressure to a value slightly below or slightly above atmospheric pressure, depending on operating conditions and design specifications. It is a labyrinth seal with a stepped portion having a step portion, and constitutes a two-stage seal. The high pressure stage ring 34a is of the sleeve type with seven flange with diametrical splits. When the inner surface of the 7 flange is fastened to the bearing housing 36, two annular collection chambers 72a and 721 are connected to each other by a radial passage 720 between islands 726.
). The high-pressure stage ring 34a of the seal ring 34 is fastened to the bearing housing 36 by a pole passing through the island-like projection 72C1. The low pressure stage ring 34b of the seal ring 34 is of the split sleeve type supported by the bearing housing 313-6 by means of a lug-full connection.

The bearing housing 36 is suitably constructed as a gray cast iron piece with a horizontally extending split. Bearings 38 and 39 are inclined pad type sital bearings. The journal load is light and the surface speed is moderate. Further, the thrust load of the wheel is matched so that the residual thrust load is absorbed by a fixed pad type thrust bearing formed integrally with the journal assembly.

Wheel 26 is of an overhung flexible shaft design as shown, and may or may not be integral with shaft 28, depending on design operating conditions. In the middle stage turbine it is possible to form the wheel and shaft in one piece. However, in a two-stage turbine, whether or not these members are integrated depends on the back pressure acting on the back surface of the second-stage wheel 26h. Due to back pressure, among other factors, 14
- The number of seal teeth required is determined. Wheel dynamics determine which overhangs are allowed. With these two points, what kind of l! I! It is determined whether a similar shaft/disk structure should be employed. In the two-stage turbine shown, the first stage wheel 26a and the second stage wheel 261) are integral. The method adopted to connect the wheel 26 and the shaft 28 is, for example, a shaft 7/disk structure with a simple flange fastened with bolts or a polygonal cross-sectional fit. It depends on the rotation speed of 20. As will be explained in more detail below, aerodynamic passages or buffs h 30 a and 30 b are formed in the disks of the first stage wheel 26 a and the second stage wheel 26 I, respectively. Wheel 26 is suitably made of stainless steel as described above, and shaft 28 is suitably made of chromium-molybdenum steel. The bearing housing 36, i.e. the back side of the wheel 26 in the box 7, is used as a balance piston in the case of a second stage turbine.

As shown in the drawings, labyrinth seal '11, 42, 44 is a straight type without a splint (C), labyrinth seal/13 is a straight type without a splint (c), but has a stepped portion. may have a stepped portion or may not have a stepped portion. If the labyrinth seal 45 has a stepped portion (not shown), the diameter of the stepped portion gradually increases as the wheel 26 moves laterally when the labyrinth seal 45 has a step (not shown). Since J: or b decreases, as long as <K, the labyrinth seal 43 must be provided with a split. These labyrinth seals act to control the leakage of high pressure steam to balance the thrust load injected onto the back surface of the wheel 26. The carbon seal 46 is the bearing 6
To prevent moisture from entering the old bearing housing 36.
It is designed to retain the oil inside. The carbon seal 46 may replace the labyrinth seal as in conventional turbines with a source of slightly pressurized air that leaks into the C bearing housing 36 and into the turbine.

The machining process for forming the aerodynamic passage or packet 30 is substantially the same regardless of whether the first stage buffet 30a or the second stage buffet 30a is used to form a general packet 30. I will explain the machining process.

In FIGS. 3 and 4, the wheel 2G is supported on an indexed table (4" not shown) for machining, and the axis of the table is perpendicular to the axis 54 of the end mill cutter 52. The axis 54 of the end mill cutter 52 has two degrees of freedom of movement relative to a vertical plane 50 passing through the axis of the wheel 26. The two degrees of freedom of movement of the axis 54 are best shown in FIG. (As shown, the rotating end mill cutter 52
along the path indicated by the arrow 52a) along the plane 5.
0, then move along the semi-circular path indicated by arrow 52 II, then move along the semicircular path indicated by arrow 52
It is numerically controlled to move perpendicular to the plane 50 along the path indicated by . When machining the end mill cutter 521 or the buff i-3〇17-, the island-like protrusion 31 is left behind. Once the machining of buffs 1 to 30 is completed, the wheel 26 is rotated by a certain amount of varus as determined by the particular design and the machining steps of steps 1 to 3 are repeated.

This machining process is repeated until the entire rim portion of wheel 26 has been machined to form a series of evenly spaced and overlapping packets 30.

In the case of a two-stage wheel, the cutter settings are varied but the small machining steps are repeated for each stage. A two-stage wheel 26 thus machined is shown in FIG. In order to machine the various packets in various internal longitudinal directions in order to obtain a sweeping aerodynamic path, an offset cutter [
- and avoid varying the vertical height of the cutter 52 with respect to the indexed table ().In addition, if it is necessary that a part of the cutting part be wider than the diameter of the cutter 52, Although it is necessary to form two cutting parts with the cutter 52, the island-like protrusion 31 does not need to be provided at the center.

18- Form the small eel bucket 30 as described above.
: sealing between the inlet and outlet +=i of the wheel 26 by means of labyrinth seals 41 and 7I2 for (the first stage 26a and the second stage 261, respectively) (thereby, a number of results are achieved. By pushing the small metal island 31, a 180'' curved guided passage is obtained. ) Increases the work done by a given wheel in a similar manner.Firstly, the island-like protrusions 31 are installed on the buffs 1 to 1, which increases the flow rate. - From filtration steam 7] ~
A suction side surface 31a (similar to a normal 180° curved surface) is formed which transmits more power to the cap.

If the island-like protrusion 31 is not stepped (-1 to 6. A vortex is generated which dissipates the potential /i energy that would otherwise be recovered.

Second, as best shown in FIG. 6, a sealing effect is achieved by labyrinth seals 711 and 42 between the inlet and outlet of the packet 31 in the first and second stages, respectively. , and since quality ftl and energy are conserved, the energy loss is reflected as a static pressure drop across each stage of wheel 26. This amount of reaction (estimated to be on the order of 5-10%) further increases the work done by the resulting wheel.

Depending on the design h1 conditions, the reaction rate 1α can be changed by changing the shape of the passage without changing the machining process. For example, the flow path converging from the inlet J of the buffs 1 to the outlet may be a buff I- with a high degree of J stiffness reaction. Such buffing forms a convergent flow path. J. It is effectively scooped by moving the insula toward the exit side. However, in this method (although the machining method is basically the same, two-sided cutting is generally required, and the changes required in case A will be obvious to those skilled in the art. To.

By eliminating a single imperforate surface delimiting the flow through the buff H-30, the surface friction caused by the fluid flowing within the buff H-30 is reduced and the J-shaped Losses are reduced. This is actually a reduction in the dissipation area due to viscosity (due to energy dissipation).

Also, this is one of the factors that cause secondary losses.
In other words, secondary loss is reduced by substantially eliminating the non-porous boundary surface. Historically, it has been decided to provide some reaction force to the wheel 26 in a reaction axial turbine (-J) in order to reduce packet loss and promote curvature. or subsidized.

In FIGS. 1, 2, and 7, steam is supplied axially to the turbine 10 through the inlet 1-casing 12. Inlet reflex 1, casing 12, returbine 1
The flow of water vapor through the exhaust volute casing 161\ through the exhaust volute casing 161 is indicated by arrows in FIG.
Inlet guide vane 1/l and nozzle blade 21
It flows to the first stage 26a of the wheel 26 through the nozzle 21a defined by the above. The water vapor passes through 308 to the buffer 1, and then a vane is installed (not installed in the diffuser 8).
0, axis 1 full guide vane 24, and the nozzle 23a defined by the nozzle blade 23 to the second stage 26b of the wheel 26. Water vapor is packet 301
), then flows into the swirl casing 16' 11 through the diffuser 81 where no vanes are installed, and is discharged from the turbine 10 via the Zyde pipe outlet 21, and is discharged from the turbine 10, which consists of the τ is used or condensed. As the water vapor passes through the packets in each stage of the wheel 26, it is diverted by 180° by the pressure side surfaces of the buffs 1~, which imparts mechanical energy to the wheel 26 (d'j L, the shaft 28 and its connection). Rotate the wheel 26 with any power generator (not shown). This operation differs significantly from the basic operation of conventional impulse turbines (1), but in the illustrated embodiment (
In conventional axial turbines, the once-through components are always radial, whereas in conventional axial turbines, the flow components are always axial.However, as mentioned above, according to the packet structure of the present invention, - Many operator benefits over traditional pre-in turbines
1 is given 4j.

Furthermore, according to the bubbler 1 of the present invention, it has a low spillage, which provides considerable advantages when used in conjunction with atmospheric water vapor or dirty gases. 1q is received. In FIG. 8, the water vapor indicated by the solid arrow 60i collides with the soil on the pressure side surface 33 of the baffles 1 to 30,
Mechanical energy of 4"J"y L is applied to the wheel 26, causing the wheel to rotate in the same direction as the water vapor is supplied, as indicated by the arrow 27.

Operation: At *degrees (J), the wheel tip speed for each stage is approximately 30-65% of the velocity of the steam supplied to that stage.

In the case of 1tII water vapor, the velocity of the enveloping water droplets present in the water vapor is often equal to the velocity of the water vapor and 1 of the wheel.
fli ICf 51 is also smaller, so the wheel 26
impinges on the water droplet 62, which often has a relative velocity of Ω to the speed of the wheel. In the conventional structure of the baffler 1, the downstream side wall of the baffle 1 is impinged by the water droplets and collides with it, thereby eroding it.However, when the bucket 30 is constructed according to the present invention, In this case, the downstream part to the conventional baffle 1 is not present and is therefore not subject to erosion. , represents the water contained in the water vapor 10 supplied to the nozzle.

The exact relative speed and direction depends on the steam stage G1 conditions. Machining of baffles 1 to 30 Li, I=, i7f
, so that the point-shaped portion 26' on the red surface of the rim portion of the wheel 2G remains after machining. Ill.

The pointed portion 26' represents the outer surface of the wheel 26 and is J-3.
This is the part where there is a smooth transition from the bottom surface 65 of the bafflers 1 to 30 to the outer surface of the wheel, and it is in a straight line with the nozzle, so each water droplet or particle 62 is If it collides with the bottom surface 65 and/or the pointed portion 26', the water vapor moves smoothly and falls into the next packet, flowing inside the bucket as shown by the arrow 66. After passing through the baffles 1 to 30, the water droplets or particles (62) captured by flow) t. The water droplet or particle 62 has a very small elongated protuberance in the pointed portion 2.
6' and the bottom surface 65 of the baffle (~), so their erosion, if any, is very slight.Furthermore, even if erosion occurs under a severe setting, the erosion will not be substantial. occurs in a region of infinite thickness, i.e. near the center of the wheel, so that the bucket
- It is unnecessary to cause mechanical damage such as occurs in conventional turbines due to breakage at the parts.

Although the present invention has been described above with respect to a two-stage steam turbine, the present invention is not limited to such embodiments.
It will be clear to those skilled in the art that r This intermediate stage may be used in conjunction with the control stage of an axial flow turbine that requires it. The bearing housing 36 may be a gearbox, and depending on the stage, the turbine may be independent as shown. It may be a device, or it may be an integral part of the gearbox. The labyrinth seals 41 and 4/l may be replaced with polishable seals.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a two-stage turbine incorporating a solid wheel of the present invention. . FIG. 2 is a partially enlarged sectional view showing the main parts of the turbine shown in FIG. 1. FIG. 3 is a partial sectional view showing the baffle 1 to the forming culm. FIG. 4 is a plan view showing the packet forming process. FIG. 5 is a partially cutaway front view of the two-stage solid wheel. FIG. 6 is a perspective view showing the bucket and its associated seal. FIG. 7 is a partial cross-sectional view showing the nozzle structure in a two-stage solid wheel turbine. FIG. 8 is a perspective view of the packet showing fluid flow. 10...Turbine, 12...In-1 knot casing. 16...Exhaust swirl casing, 18...Swirl cover. 20... Nozzle ring, 21... Nozzle blade,
22... Nozzle assembly, 23... Nozzle blade,
24... Axial guide vane, 26... Wheel, 28... Shaft, 30... Bucket, 31...
...island. 32...Balance screw [・N seal ring, 33...
・Pressure side surface, 34...Shaft seal ring, 36
...Bearing housing, 38.39...Bearing, 41~
45... Labyrinth seal, 46... Carbon seal, 50... Vertical plane, 52... End mill cutter, 54... Axis line, 62... Water drop, 65... Bottom surface,
80.81...Difcoza Special Ff Applicant: T Riot Turbomachinery Company, Inc.

Claims (4)

[Claims] (1) a solid wheel having at least one circumferentially extending rim portion having a predetermined width; a plurality of packets, each of said buffs having two legs connected by a curved portion;
12. A turbine wheel comprising: a turbine wheel defining a letter-shaped passageway, said curved portion having a diameter less than said predetermined width, and said leg portion extending to said rim portion. (2) having a flow path having an inlet and an outlet [1 installed at the same time], a nozzle ring and a turbine wheel constituting a part of the flow path, the wheel having a first width of a predetermined width; It has a rim portion extending in the circumferential direction, and a plurality of packets are formed in the rim portion uniformly spaced over the entire circumference and overlapping each other, and each of the packets has a ε
, defining a substantially U-shaped passage having two legs connected by a curvature, said curvature having a diameter less than said predetermined width, said legs having a diameter smaller than said predetermined width; An Ili percussion turbine, characterized in that the Ili percussion turbine extends to the rim portion. (3) an impulse turbine having gauging including an axial inlet and a radial outlet, with uniformly spaced and i-discretely formed substantially ( )-shaped buffs; a first radial inflow nozzle surrounding said rim portion and providing substantially tangential flow to said packet of said turbine wheel device; a ring arrangement; the packet and radial inflow nozzle ring arrangement defining a portion of a fluid passageway fluidly communicating the axial inlet and the radial outlet; An impact turbine featuring: (4) A turbine wheel made from a material having at least one rim portion having a predetermined width fi! By using the lI manufacturing method, the outer diameter of the U-shaped curved portion is smaller than the predetermined width J.
forming a substantially U-shaped packet in the rim of the material, the legs of the ``('' extending up to the rim; and in the same manner around the entire circumference of the rim. add additional uniformly spaced f17j-dispersed U-shaped packets to i
A method characterized by forming a number and containing lυ.